What do greenhouse gases have to do with global warming?-?

Question

HEELP

Answer 1

The Greenhouse Effect occurs when visible light come into a system and is converted into infrared radiation (heat) before it can leave, thus generating a net increase of energy in the system.

An example is what happens in your car on a sunny day. Visible light comes in through the windows and heats the air. This generates infrared light (which ordinary window glass is not transparent to). As more sunlight comes in the temperature continues to rise, until the car is blistering hot inside.

Greenhouse gases -- most notably carbon dioxide and methane -- do the same thing on a global scale. To relate this to the example, the Earth is like your car and the greenhouse gases are like the windows. Incoming visible light from the Sun passes through the greenhouse gases, but outgoing infrared light from the Earth cannot. This contributes to a net increase in global temperature. That increase is _very_ small in such a large system, though; when scientists talk about global warming, they're referring to an increase of 1-2 degrees in the average global temperature over the course of several decades.

Answer 2

They are called greenhouse gases because they make the atmosphere act like a green house keeping heat in. CO2 and others make a layer that when heat from the sun bounces off the earth, it bounces back to the earth again instead of going out into space. If you notice that on a clear night it gets colder than on a cloudy night, it is the same. Clouds act to reflect the heat the earth is reradiating back and keep us warm. On a clear night the heat goes out into space and we are colder.

Answer 3

http://www.epa.gov/climatechange/kids/greenhouse.html